Collapsing tap



' Jan. 4, 1927.

' c. J. KNAPP COLLAPSING TAP Filed vJuly 30. 1923 Patented Jan. 4, 1927. 1

UNITED STATES PATENT GFF'ICE.

CHARLES J. KNAPP, F ERIE, .E'ENNSYLVANIA.

COLLAPSING TAP.

Application filed July 30, 1923. Serial No. 654,592.

The-present structure is superior not only relatively to the cutter in a reverse direcin simplicity and adaptability of the struction to the bevel of the ends of the cutter. ture for all sizes of taps but it isparticularly The ends of the projections 16 have a suradvantageous in its possibility for very face 19 parallel with a cuttin axis of the a small sizes of collapsing taps and also in tap which forms a locking surface for lock- 60 that it permits of the cutters extending-pracing the cutter in its outward position. tically to theend of the tap so that a thread The cam and locking pin 13 has a cam may be carried with a collapsing tappracsurface 20 at its end which is adapted to tically to the bottom of a screw socket as engage the surface 17 of the cutters as they with an ordinary plug tap. These features are moved rearwardly through the movement 05 and others described in the specification and of the sleeve 4 and thus moves the cutters claims form the objects of the invention. outwardly into operative position. The pin The invention is illustrated in the accomalso. has locking surfaces 21 on which the panying drawings as follows surfaces 19 are brought at the completion of Fig. 1 shows a central section of the tie the setting movement. These surfaces, there- 7 vice on the line 1-1 in Fig. 2. fore, lock the cutters in their outer position Fig. 2 a side elevation. and hold them accurately to position. Fig. 3 an end view. In order to retract the cutters a cam plug Fig. 4 a section on the line 4-4 in Fig. l. 22 is slidably mounted in the end of an open- Fig. 5 a section on the line.5-5 in Fig. 1. ing 4 extending through the sleeve 4. It {I Fig. 6 a section on the line 6-6 in Fig. 1. has the cam surfaces 23 acting on the sur- 1 marks the head. This has a flat sided faces 18 of the projections and is yieldingly extension 2 with a cylindrical projection 3. held against said surfaces by a spring 24, the

A cutter holding sleeve 4 is mounted on the spring being locked in the socket or opening 2 extension 2 having a socket conforming to 4" by a cap v screwed into the end of the the shape of the extensionso that the sleeve socket. It will be noted that the plug 22 is driven by the extension. The sleeve is forms a guide and support for the endof slidingly mounted on the extension and has the cam pin 13 and-also even with the cutters a collar 5 secured thereon by a screw 6, the in their outer position the plugstill engages 3U collar moving with the sleeve and operating the surfaces 18 so as to prevent the disen- I to all intents and purposes as an integral gagement or further outward movement of art. i the cutters. v

The sleeve has the cutter holding slots 7 In order to move the sleeve to operate the in which cutters 8 are. arranged. The cutcutters some sort of trip device is provided. ters have the beveled ends 9 and 10 these In the presentconstruction a lever 26 is piv- 0 ends being parallel and slide against suroted on a pin 27- and extends through a slot faces 11 and 12 at the ends of the slots 7. 28 in the sleeve 4-and collar 5 int-oaslot 29 in By this construction the end of the cutter the pin 13. The lever may be moved by may be brought flush with the extremeend hand to reset the tap, or by forcing the of the holder so that the threads may be. carsleeve to the position shown in Fig. 1, or. it ried to the bottom of a screw threaded maybe arranged to engage a stationary part socket. This is possible because the inclinaof the machine as the'tap is retracted for aution of the wall orend 11 furnishes metal tomatically affecting this purpose. for joining the holding sleeve and giving In order to adjust the expanded, posit-ion rigidity to the parts while thecuttingedge of the cutters it is desirable to have some or face of the cutter due tothe bevel or inmeans whereby the locking surfaces may be clination extends entirely to the end. slightly varied to vary the adjustment. This A cam and locking pin 13 has a screwis readily accomplished in the present structhreaded end 14 which is secured in a screw ture as follows :-A pin 30 extends from the threaded socket 15 in. the projections 2 and locking pin 13 outwardly through a slot 31 3 on the head, the pin thus being assembled in the sleeve 4 into an opening 32 in a coland held rigid with the head. The cutters lar 33. A lug 34- extends outwardly from have the cam projections 16 with the rearthe sleeve 4 into a socket 35 in the collar 33. ward and forward cam surfacesl? and 18, Adjusting screws 36 are arranged in the col these cam surfaces being beveled or inclined lar each side of the lug 34.. By adjusting the screws 36 the collar may be swung on the sleeve t swinging the pin 13, the screw threads 14 permitting this, so as to vary slightly the position of the flats 21, these flats under these conditions acting as a cam so as to extend the axial movement outwardly slightly or inwardly slightly in order to accurately position the cutters.

In the operation of the device as the sleeve is drawn forward relatively to the pin 13 the surfaces 19 are carried off the locking surfaces 21 and the cutters permitted to re tract inwardly, the cam action of the cam plug 22 together with whatever strain the cutters are subjected to affecting this movement. Upon a reverse of this movement of the sleeve 4. through the action of the lever 26 the cutters are forced outwardly by the cam surface 20 on the surface 17 and as these cutters are carried on to the locking surfaces locked in their outer position.

What I claim as new is 1. In a collapsing tap, the combination of a holder having radially extending slots, the end walls of the slots being parallel and inclined to the axis and opening at their outer ends adjacent to the end of the holder, the ends of the slots adjacent to the end of the holder being closed by a wall bridging the ends of the slots; cutters having beveled and parallel ends operating in the slots; and tripactuated means positioning the cutters in the slots.

2. In a collapsing tap, the combination of a holder having radially extending slots, the end walls of the slots being parallel and inclined to the axis and opening at their outer ends adjacent to the end of the holder, the ends of the slots adjacent to the end of the holder being closed by a wall bridging the ends of the slots; cutters having beveled and parallel ends operating in the slots; and trip-actuated means positioning the cutters in the slots comprising devices moving the cutters outwardly and locking them in their outer position.

3. In a collapsing tap, the combination of a holder having radially extending slots, the end walls of the slots being parallel and inclined to the axis and opening at their outer ends adjacent to the end of the holder, the ends of the slots adjacent to the end of the holder being closed by a wall bridging the ends of the slots; cutters having beveled and parallel ends operating in the slots; and trip-actuated means positioning the cutters in the slots comprising devices moving the cutters outwardly and inwardly and locking them in their outer position.

4. In a collapsing tap, the combination of a. holder having radially extending slots, the end walls of the slots being parallel and inclined to the axis and opening at their outer ends adjacent to the end of the holder, the ends of the slots adjacent to the end of the holder being closed by a wall bridging the ends of the slots; cutters having beveled and parallel ends operating in the slots; and trip-actuated means positioning the cutters in the slots comprising cam bevels on the cutparallel ends operating in the slots rand tripactuated means positioning the cutters in the slots comprising cam bevels on the cutters extending in a reverse direction from the bevels on the ends of the cutters and a cam pin acting on the cam bevels and having an axially extending locking surface acting on the cutters to lock them in open position.

6. In a collapsing tap, the combination of a holder having radially extending slots, the end walls of the slots being parallel and inclined to the axis and opening at their outer ends adjacent to the end of the holder, the ends of the slots adjacent to the end of the holder being closed by a wall bridging the ends of the slots; cutters having beveled and parallel ends operating in the slots; trip-- actuated means positioning the cutters in the slots comprising devices moving the cutters outwardly and locking them in their outer positions; and means adjusting the outward locked position of the cutters.

7 In a collapsing tap, the combination of a cutter having parallel beveled ends; the forward end forming an acute angle to the cutting face of the cutter; a holder having slots conforming to the shape of the cutter; means positioning the cutter in the slots comprising a cam bevel on the cutter extending in a reverse direction from the end of the cutter and a cam pin acting on the cam bevel and having a locking surface acting on the cutter to lock it in open position; and means acting on the pin adjusting the locking surface to adjust the outward locking position of the pin.

8. In a collapsing tap, the combination of a holder having radially extending slots, the end walls of the slots being parallel and inclined to the axis and opening at their outer ends adjacent to the end of the holder, the ends of the slots adjacent to the end of the holder being closed by a wall bridging the ends of the slots; cutters having beveled and parallel ends operating in the slots; double cam projections on each of the cutters havmg front and rear cam surfaces extending in r a reverse direction from that of the ends of the cutters; and trip-actuated means acting on the cam surfaces for moving the cutters lUll lit)

in and out to collapsed and expanded position.

9. In a collapsing cap, the combination of a holder having radially extending slots, the end Walls of the slots being parallel and inclined to the axis and opening at their outer ends adjacent to the end of the holder, the ends of the slots adjacent to the end of the holder being closed by a Wall bridging the ends of the slots; cutters having beveled and parallel ends operating in the slots; double cam projections on each of the cutters having front and rear cam surfaces extending in a reverse direction from that of the ends of the cutters; trip-actuated means acting on the cam surfaces for moving the cutters in and out to collapsed and expanded position; and means acting on the projections for locking the cutters in expanded position.

10. In a collapsing tap, the combination of a head; a holder sleeve locked against rotation relatively to the head but slidingly mounted thereon; a cam pin extending from the head; a lever acting on the pin and sleeve to effect a relative movement thereto; said sleeve having cutter slots therein having beveled ends; cutters in the slots conforming to the shape of the slots and having parallel beveled ends, the cutters having cam projections having cam surfaces extending in a reverse direction from the beveled ends of the slots; cam surfaces on the cam pin acting on the projections for expanding the cutters; means on the pin for locking the cutters in expanded position; and a collapsing plug having a cam operating on the projections to retract the cutters.

11. In a collapsing tap, the combination of a head; a holder sleeve locked against rotation relatively to the head but slidingly mounted thereon; a cam pin extending from the head; a lever acting on the pin and sleeve to effect a relative movement thereto, said sleeve having cutter slots therein having beveled ends; cutters in the slots con forming to the shape of the slots and having parallel beveled ends, the cutters having cam projections having cam surfaces ex tending in a reverse direction from the beveled ends of the slots; cam surfaces on the cam pin acting on the projections for ex panding the cutters; means on the pin for locking the cutters in expanded position; a collapsing plug having a cam operating on the pro ections to retract the cutters; and a spring acting on the plug for yieldingly actuating the same.

12. In a collapsing tap the combination of a cutter; a holder sleeve having a slot in which the cutter is mounted; a cam pin operating to move the cutter outwardly, said cam pin having locking surfaces thereon for locking the cutter in expanded position; and means for rotating the sleeve relatively to the cam pin relatively to the plunger to vary the locking position to adjust the expanded position of the cutter.

In testimony whereof I have hereunto set my hand.

CHARLES J. KNAPP. 

